Vascular prostheses of different porosity (Cooley Very Soft; Miliknit Lo-Por; Microvel; Sparks Mandril) were pretreated with fibrin glue and the permeability was assessed both in vitro and in 12 dog experiments by descending aorta replacement under full systemic heparinization. It was found that all types of prostheses were completely sealed after the pretreatment. In 28 patients undergoing descending or abdominal aorta replacement under systemic heparinization high porosity knitted Dacron grafts were pretreated with the fibrin glue only. There was no blood loss across the prosthetic wall. It is concluded that graft-pretreatment with fibrin glue allows for combining full heparinization and the use of high porosity vascular grafts.